If calendars were still a thing for 27-year-olds, Mike Glennon would have drawn a red circle around Sept. 17 and written in "Bears at Bucs." This isn't just another game for him, and to his credit he's not pretending it is.

Glennon, the Bears quarterback, enjoyed his four seasons in Tampa after the Buccaneers drafted him in the third round. They developed him in three separate offensive systems, and he started 18 games from 2013 to 2014.

The Bucs regarded him well enough that in March they were prepared to pay him about $8 million annually in a multi-year deal to stay and back up Jameis Winston.

Of course, Glennon found a better opportunity and a bigger payday with the Bears, so he'll be on the visitors' side Sunday. Who knows how many chances he'll have in a Bears uniform to get a win as special as this would be?

"It's just human nature," Glennon said, "to be looking forward to this a little more."

If Glennon succeeds Sunday and, beyond that, for however long his run as the Bears' starter lasts, his former co-workers wouldn't be surprised.

Photos of Bears quarterback Mike Glennon.

Pro Bowl receiver Mike Evans was a rookie in 2014 when Glennon started five games. The first of his 27 career touchdowns came out of Glennon's right hand.

"He could see over the line really, really good," Evans said. "A lot of other quarterbacks are shorter than him, so it'll be harder to see. But when he's in there, it's easy for him to see in the pocket. He's a smart player, and his arm talent is really good."

Second-year coach Dirk Koetter dissected video of Glennon's season-opening performance against the Falcons and saw what he expected, particularly in how Glennon avoided interceptions.

"Mike takes care of the football," Koetter said. "He's a very accurate passer. He's an excellent leader. It didn't surprise me one bit that he was elected captain there in Chicago. They had chances to win the game at the end. That's all you can ask in every game."

Giving the Bears a chance late in the game also met Dowell Loggains' criteria. Most importantly to the Bears offensive coordinator, Glennon didn't turn the ball over. In doing so, helped move the Bears 5 yards from a win that ultimately escaped them.

Loggains seized on the positives, complimenting Glennon by saying he "managed the game."

"Sometime that phrase can be misconstrued," Loggains said. "When I say managed the game — he did exactly what he needed to do to play the game we detailed out to him, how we thought we could win the game, and what was best for us and that matchup. He handled all the situations, did a really good job."

Glennon completed 26 of 40 passes for 213 yards and a touchdown. Among the negatives: He was sacked four times, including on the decisive fourth-and-goal with eight seconds remaining in the 23-17 loss.

Brad Biggs and Dan Wiederer break down the Bears' Week 1 loss to the Falcons on Sept. 10, 2017.

Brad Biggs and Dan Wiederer break down the Bears' Week 1 loss to the Falcons on Sept. 10, 2017.

Glennon was self-critical for taking a sack on a first down earlier in the game. But neither he nor Loggains was apologetic about Glennon's relative lack of escapability.

There were times Sunday when the Bears would have benefited from rookie Mitch Trubisky's athleticism, specifically his ability to create behind the line of scrimmage. But rather than harping on that, Loggains is determined to maximize what Glennon does well.

"Mike is … a timing and a rhythm thrower," Loggains said. "He's going to take advantage of what the defense does, and if they're playing soft, he's going to take underneath throws. He's going to be aggressive when it's time to take his shots.

"It's important that we keep him clean in the pocket because he's not, in his words, a dual-threat quarterback. He's going to win before the snap. He's going to know what the coverage is, what the tells of the defense are."

Said Glennon: "I know what I do well, and I'm not going to try to be more mobile. I'm just going to stick to who I am and just find more ways to execute."

That challenge for Sunday involves overcoming the attrition at receiver. With Kevin White joining Cameron Meredith on injured reserve, both receivers with whom Glennon practiced the most are out.

Not that Glennon's former teammates are willing to extend sympathy. One of his good friends, five-time Pro Bowl defensive tackle Gerald McCoy, is ready for Glennon's best.

"I shot him a message and told him, 'I'm proud of you, man. You played well,'" McCoy said. "I'm excited to compete against him. I'm looking forward to it, but I'm not looking forward to it — because he is that good."